Color imaging devices contain two or more cartridges. Each transfers a different color of toner to a media sheet as required to produce a full color copy of a toner image. A common imaging device includes four separate color cartridges—cyan, yellow, magenta, and black. Image formation for each of the four colors includes moving toner from a toner reservoir to an imaging unit where toned images are formed on a photoconductive (PC) drum prior to transfer to a media sheet or to an intermediate transfer member (ITM) for subsequent transfer to a media sheet.
In many imaging devices, each color has a dedicated supply of power for setting voltages for charging its PC drum and biasing a developer roll between the toner reservoir and charged drum. In others, power supplies are combined for cyan, magenta and yellow, while black maintains its own dedicated supply. The former provides superior toner usage results and color accuracy. The latter provides economic efficiency. The inventors have identified a need for managing color accuracy and toner usage when all cartridges have but a single common voltage supply.